Principle: By using a scanning device to detect positron (subatomic particles) emitted by the radionuclide in the organ or tissue being examined. A PET scan uses a radioactive drug (tracer) to show this activity. The radioactive drug may be injected, swallowed or inhaled, based on which organ or tissue is being evaluated by the PET scan. Positrons are emitted by a breakdown of the radionuclide then gamma ray is created and the scanner then detects the gamma rays a computer analyses the gamma rays to create an image of the organ or tissue being studied. The tracer collects in areas of the body that have maximum levels of chemical activity, which often correspond to areas of disease. On a PET scan, these areas show up as bright spots. The radiotracer
